/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.sun.org.apache.xerces.internal.impl.dv.xs;

import com.sun.org.apache.xerces.internal.impl.dv.InvalidDatatypeValueException;
import com.sun.org.apache.xerces.internal.impl.dv.ValidationContext;

/**
 * Validator for <precisionDecimal> datatype (W3C Schema 1.1)
 *
 * @author Ankit Pasricha, IBM
 * @xerces.experimental
 */
class PrecisionDecimalDV extends TypeValidator {

  static final class XPrecisionDecimal {

    // sign: 0 for absent; 1 for positive values; -1 for negative values (except in case of INF, -INF)
    int sign = 1;
    // total digits. >= 1
    int totalDigits = 0;
    // integer digits when sign != 0
    int intDigits = 0;
    // fraction digits when sign != 0
    int fracDigits = 0;
    //precision
    //int precision = 0;
    // the string representing the integer part
    String ivalue = "";
    // the string representing the fraction part
    String fvalue = "";

    int pvalue = 0;


    XPrecisionDecimal(String content) throws NumberFormatException {
      if (content.equals("NaN")) {
        ivalue = content;
        sign = 0;
      }
      if (content.equals("+INF") || content.equals("INF") || content.equals("-INF")) {
        ivalue = content.charAt(0) == '+' ? content.substring(1) : content;
        return;
      }
      initD(content);
    }

    void initD(String content) throws NumberFormatException {
      int len = content.length();
      if (len == 0) {
        throw new NumberFormatException();
      }

      // these 4 variables are used to indicate where the integre/fraction
      // parts start/end.
      int intStart = 0, intEnd = 0, fracStart = 0, fracEnd = 0;

      // Deal with leading sign symbol if present
      if (content.charAt(0) == '+') {
        // skip '+', so intStart should be 1
        intStart = 1;
      } else if (content.charAt(0) == '-') {
        intStart = 1;
        sign = -1;
      }

      // skip leading zeroes in integer part
      int actualIntStart = intStart;
      while (actualIntStart < len && content.charAt(actualIntStart) == '0') {
        actualIntStart++;
      }

      // Find the ending position of the integer part
      for (intEnd = actualIntStart; intEnd < len && TypeValidator.isDigit(content.charAt(intEnd));
          intEnd++) {
        ;
      }

      // Not reached the end yet
      if (intEnd < len) {
        // the remaining part is not ".DDD" or "EDDD" or "eDDD", error
        if (content.charAt(intEnd) != '.' && content.charAt(intEnd) != 'E'
            && content.charAt(intEnd) != 'e') {
          throw new NumberFormatException();
        }

        if (content.charAt(intEnd) == '.') {
          // fraction part starts after '.', and ends at the end of the input
          fracStart = intEnd + 1;

          // find location of E or e (if present)
          // Find the ending position of the fracion part
          for (fracEnd = fracStart;
              fracEnd < len && TypeValidator.isDigit(content.charAt(fracEnd));
              fracEnd++) {
            ;
          }
        } else {
          pvalue = Integer.parseInt(content.substring(intEnd + 1, len));
        }
      }

      // no integer part, no fraction part, error.
      if (intStart == intEnd && fracStart == fracEnd) {
        throw new NumberFormatException();
      }

      // ignore trailing zeroes in fraction part
            /*while (fracEnd > fracStart && content.charAt(fracEnd-1) == '0') {
             fracEnd--;
             }*/

      // check whether there is non-digit characters in the fraction part
      for (int fracPos = fracStart; fracPos < fracEnd; fracPos++) {
        if (!TypeValidator.isDigit(content.charAt(fracPos))) {
          throw new NumberFormatException();
        }
      }

      intDigits = intEnd - actualIntStart;
      fracDigits = fracEnd - fracStart;

      if (intDigits > 0) {
        ivalue = content.substring(actualIntStart, intEnd);
      }

      if (fracDigits > 0) {
        fvalue = content.substring(fracStart, fracEnd);
        if (fracEnd < len) {
          pvalue = Integer.parseInt(content.substring(fracEnd + 1, len));
        }
      }
      totalDigits = intDigits + fracDigits;
    }

    // Construct a canonical String representation of this number
    // for the purpose of deriving a hashCode value compliant with
    // equals.
    // The toString representation will be:
    // NaN for NaN, INF for +infinity, -INF for -infinity, 0 for zero,
    // and [1-9].[0-9]*[1-9]?(E[1-9][0-9]*)? for other numbers.
    private static String canonicalToStringForHashCode(String ivalue, String fvalue, int sign,
        int pvalue) {
      if ("NaN".equals(ivalue)) {
        return "NaN";
      }
      if ("INF".equals(ivalue)) {
        return sign < 0 ? "-INF" : "INF";
      }
      final StringBuilder builder = new StringBuilder();
      final int ilen = ivalue.length();
      final int flen0 = fvalue.length();
      int lastNonZero;
      for (lastNonZero = flen0; lastNonZero > 0; lastNonZero--) {
        if (fvalue.charAt(lastNonZero - 1) != '0') {
          break;
        }
      }
      final int flen = lastNonZero;
      int iStart;
      int exponent = pvalue;
      for (iStart = 0; iStart < ilen; iStart++) {
        if (ivalue.charAt(iStart) != '0') {
          break;
        }
      }
      int fStart = 0;
      if (iStart < ivalue.length()) {
        builder.append(sign == -1 ? "-" : "");
        builder.append(ivalue.charAt(iStart));
        iStart++;
      } else {
        if (flen > 0) {
          for (fStart = 0; fStart < flen; fStart++) {
            if (fvalue.charAt(fStart) != '0') {
              break;
            }
          }
          if (fStart < flen) {
            builder.append(sign == -1 ? "-" : "");
            builder.append(fvalue.charAt(fStart));
            exponent -= ++fStart;
          } else {
            return "0";
          }
        } else {
          return "0";
        }
      }

      if (iStart < ilen || fStart < flen) {
        builder.append('.');
      }
      while (iStart < ilen) {
        builder.append(ivalue.charAt(iStart++));
        exponent++;
      }
      while (fStart < flen) {
        builder.append(fvalue.charAt(fStart++));
      }
      if (exponent != 0) {
        builder.append("E").append(exponent);
      }
      return builder.toString();
    }

    @Override
    public boolean equals(Object val) {
      if (val == this) {
        return true;
      }

      if (!(val instanceof XPrecisionDecimal)) {
        return false;
      }
      XPrecisionDecimal oval = (XPrecisionDecimal) val;

      return this.compareTo(oval) == EQUAL;
    }

    @Override
    public int hashCode() {
      // There's nothing else we can use easily, because equals could
      // return true for widely different representation of the
      // same number - and we don't have any canonical representation.
      // The problem here is that we must ensure that if two numbers
      // are equals then their hash code must also be equals.
      // hashCode for 1.01E1 should be the same as hashCode for 0.101E2
      // So we call cannonicalToStringForHashCode - which implements an
      // algorithm that invents a normalized string representation
      // for this number, and we return a hash for that.
      return canonicalToStringForHashCode(ivalue, fvalue, sign, pvalue).hashCode();
    }

    /**
     * @return
     */
    private int compareFractionalPart(XPrecisionDecimal oval) {
      if (fvalue.equals(oval.fvalue)) {
        return EQUAL;
      }

      StringBuffer temp1 = new StringBuffer(fvalue);
      StringBuffer temp2 = new StringBuffer(oval.fvalue);

      truncateTrailingZeros(temp1, temp2);
      return temp1.toString().compareTo(temp2.toString());
    }

    private void truncateTrailingZeros(StringBuffer fValue, StringBuffer otherFValue) {
      for (int i = fValue.length() - 1; i >= 0; i--) {
        if (fValue.charAt(i) == '0') {
          fValue.deleteCharAt(i);
        } else {
          break;
        }
      }

      for (int i = otherFValue.length() - 1; i >= 0; i--) {
        if (otherFValue.charAt(i) == '0') {
          otherFValue.deleteCharAt(i);
        } else {
          break;
        }
      }
    }

    public int compareTo(XPrecisionDecimal val) {

      // seen NaN
      if (sign == 0) {
        return INDETERMINATE;
      }

      //INF is greater than everything and equal to itself
      if (ivalue.equals("INF") || val.ivalue.equals("INF")) {
        if (ivalue.equals(val.ivalue)) {
          return EQUAL;
        } else if (ivalue.equals("INF")) {
          return GREATER_THAN;
        }
        return LESS_THAN;
      }

      //-INF is smaller than everything and equal itself
      if (ivalue.equals("-INF") || val.ivalue.equals("-INF")) {
        if (ivalue.equals(val.ivalue)) {
          return EQUAL;
        } else if (ivalue.equals("-INF")) {
          return LESS_THAN;
        }
        return GREATER_THAN;
      }

      if (sign != val.sign) {
        return sign > val.sign ? GREATER_THAN : LESS_THAN;
      }

      return sign * compare(val);
    }

    // To enable comparison - the exponent part of the decimal will be limited
    // to the max value of int.
    private int compare(XPrecisionDecimal val) {

      if (pvalue != 0 || val.pvalue != 0) {
        if (pvalue == val.pvalue) {
          return intComp(val);
        } else {

          if (intDigits + pvalue != val.intDigits + val.pvalue) {
            return intDigits + pvalue > val.intDigits + val.pvalue ? GREATER_THAN : LESS_THAN;
          }

          //otherwise the 2 combined values are the same
          if (pvalue > val.pvalue) {
            int expDiff = pvalue - val.pvalue;
            StringBuffer buffer = new StringBuffer(ivalue);
            StringBuffer fbuffer = new StringBuffer(fvalue);
            for (int i = 0; i < expDiff; i++) {
              if (i < fracDigits) {
                buffer.append(fvalue.charAt(i));
                fbuffer.deleteCharAt(i);
              } else {
                buffer.append('0');
              }
            }
            return compareDecimal(buffer.toString(), val.ivalue, fbuffer.toString(), val.fvalue);
          } else {
            int expDiff = val.pvalue - pvalue;
            StringBuffer buffer = new StringBuffer(val.ivalue);
            StringBuffer fbuffer = new StringBuffer(val.fvalue);
            for (int i = 0; i < expDiff; i++) {
              if (i < val.fracDigits) {
                buffer.append(val.fvalue.charAt(i));
                fbuffer.deleteCharAt(i);
              } else {
                buffer.append('0');
              }
            }
            return compareDecimal(ivalue, buffer.toString(), fvalue, fbuffer.toString());
          }
        }
      } else {
        return intComp(val);
      }
    }

    /**
     * @param val
     * @return
     */
    private int intComp(XPrecisionDecimal val) {
      if (intDigits != val.intDigits) {
        return intDigits > val.intDigits ? GREATER_THAN : LESS_THAN;
      }

      return compareDecimal(ivalue, val.ivalue, fvalue, val.fvalue);
    }

    /**
     * @param val
     * @return
     */
    private int compareDecimal(String iValue, String fValue, String otherIValue,
        String otherFValue) {
      int ret = iValue.compareTo(otherIValue);
      if (ret != 0) {
        return ret > 0 ? GREATER_THAN : LESS_THAN;
      }

      if (fValue.equals(otherFValue)) {
        return EQUAL;
      }

      StringBuffer temp1 = new StringBuffer(fValue);
      StringBuffer temp2 = new StringBuffer(otherFValue);

      truncateTrailingZeros(temp1, temp2);
      ret = temp1.toString().compareTo(temp2.toString());
      return ret == 0 ? EQUAL : (ret > 0 ? GREATER_THAN : LESS_THAN);
    }

    private String canonical;

    @Override
    public synchronized String toString() {
      if (canonical == null) {
        makeCanonical();
      }
      return canonical;
    }

    private void makeCanonical() {
      // REVISIT: to be determined by working group
      canonical = "TBD by Working Group";
    }

    /**
     * @param decimal
     * @return
     */
    public boolean isIdentical(XPrecisionDecimal decimal) {
      if (ivalue.equals(decimal.ivalue) && (ivalue.equals("INF") || ivalue.equals("-INF") || ivalue
          .equals("NaN"))) {
        return true;
      }

      if (sign == decimal.sign && intDigits == decimal.intDigits && fracDigits == decimal.fracDigits
          && pvalue == decimal.pvalue
          && ivalue.equals(decimal.ivalue) && fvalue.equals(decimal.fvalue)) {
        return true;
      }
      return false;
    }

  }

  /* (non-Javadoc)
   * @see com.sun.org.apache.xerces.internal.impl.dv.xs.TypeValidator#getAllowedFacets()
   */
  @Override
  public short getAllowedFacets() {
    return (XSSimpleTypeDecl.FACET_PATTERN | XSSimpleTypeDecl.FACET_WHITESPACE
        | XSSimpleTypeDecl.FACET_ENUMERATION | XSSimpleTypeDecl.FACET_MAXINCLUSIVE
        | XSSimpleTypeDecl.FACET_MININCLUSIVE | XSSimpleTypeDecl.FACET_MAXEXCLUSIVE
        | XSSimpleTypeDecl.FACET_MINEXCLUSIVE | XSSimpleTypeDecl.FACET_TOTALDIGITS
        | XSSimpleTypeDecl.FACET_FRACTIONDIGITS);
  }

  /* (non-Javadoc)
   * @see com.sun.org.apache.xerces.internal.impl.dv.xs.TypeValidator#getActualValue(java.lang.String, com.sun.org.apache.xerces.internal.impl.dv.ValidationContext)
   */
  @Override
  public Object getActualValue(String content, ValidationContext context)
      throws InvalidDatatypeValueException {
    try {
      return new XPrecisionDecimal(content);
    } catch (NumberFormatException nfe) {
      throw new InvalidDatatypeValueException("cvc-datatype-valid.1.2.1",
          new Object[]{content, "precisionDecimal"});
    }
  }

  @Override
  public int compare(Object value1, Object value2) {
    return ((XPrecisionDecimal) value1).compareTo((XPrecisionDecimal) value2);
  }

  @Override
  public int getFractionDigits(Object value) {
    return ((XPrecisionDecimal) value).fracDigits;
  }

  @Override
  public int getTotalDigits(Object value) {
    return ((XPrecisionDecimal) value).totalDigits;
  }

  @Override
  public boolean isIdentical(Object value1, Object value2) {
    if (!(value2 instanceof XPrecisionDecimal) || !(value1 instanceof XPrecisionDecimal)) {
      return false;
    }
    return ((XPrecisionDecimal) value1).isIdentical((XPrecisionDecimal) value2);
  }
}
